Air-door.



N0. 743,572. PATBNTED Nov. lo, 1903.

I'. SGBWITALLA & P. FIEBIG.

AIR DOQR.

AvPPLIULTION FILED HOV. 12, 1902. H0 MODEL. 2 SHEETS-SHEET 1.

UNITED STATES 'atented November 10, 1903 PATENT OFFICE.

FRIEDRICH SCHWITALLA, OF SCHWlENTOCHLOWITZ, AND PAUD FIEBIG, OF ANTONIENHUTTE, GrERlYIANY.V

AIR-DOOR.

SPECIFICATION forming part 'of Letters Patent No. 743,572, dated November 10, 1903.

Application iiled November 12. 1902. Serial No. 131,053. (No model.)

To tu whom, it may concern:

Be it known that we, FRIEDRICH SoHWI- TALLA, residing at Schwientochlowitz, and PAUL FIEBIG, residing at Antonienhttc, Silesia, Germany, Subjects of the German Emperor, have invented an Improved Air- Door, of which the following is a full, clear, and exact description.

The present invention relates to air-doors, and has for its purpose to open and close them automatically.

The improved door may be used in waterlevel drifts as well as for transportation on an inclined plane by means of a rope orachain, no matter from which direction the truck appreaches.

In order to render the present specification more easily intelligible, reference is had to the accompanying drawings, in which- Figure l is a longitudinal section of the door. Fig. 2 is a horizontal section on line A B of Fig. 1, the rails at the left-hand sidebeing shown in dotted lines. Fig. 3 is a section on line C D of Fig. 2 looking toward the doors, and Fig. a shows the operating mechansni on an enlarged scale.

.According to the present invention the door 'is automatically opened in that the rails on which the truck is running are lowered by means of the weight of the said truck. For this purpose the rails a, are pivotally mounted on a cross-bar b and rest loosely on a cross-beam c, which is securely fixed to the lower plate d. The plate d is pivotaliy connected with the two-armed lever e, Fig. 4t, which has its fulcrum at f. An adjustable Weight g is arranged at the longer arm of the said lever, while the other end-is connected with rails t' by means of a connecting-link h, said rails being also mounted to swing vertically similarly to the rails a.

The two leaves of the door are curved to the arc of a circle in cross-section and swing on upper and lower trnnnions, forming the center of such circle when opened or closed. This rotarymovement is attained in that each door-leaf k is supported on sectors at the top and bottom, the upper sectors being pivotally supported on trunnions m, which lie in the center of the are of the circle, while the lower sectors fn, are supported on twisted edged bolts o, such bolt 0 .being revoluble on the supporting plate p. The twisted edged bolt o thus constitutes a screw with very high pitch and is guided through the female thread of the plate d. If now the plate d is moved downward by the rails ct or t being loaded, the bolts o are turned, owing .to the high pitch, and with them the door-leaves It, so that the latter are turned around the center of the arc of their circle-viz., are opened outwardly. The truck may now pass through the open door from the rails a, to the rails i', or vice versa. As soon as the rails are relieved of their weight they are raised again, together with the plate d, either by spring action or by means oi.' the counterweight g, so that by this reverse movement of the plate d a reve rse movement of the two twisted bolts y o, and thus of the door-leaves,- takes place, which`v latter now approach each other again and close the door.

We claim as our inventionf l. Thecombinationofapairofdoorscurved to the arc of a circle and having upper and lower sectors attached thereto, with upper and lower pivots forming the center of the said arc, and on which the said doors swing apart, vertically-movable rail ends leading up to they said doors from both sides in aline- V ment, and means for swinging the said doors In Witness whereof We have hereunto set our hands in presence of two Witnesses.

FRIEDRICH SCHWITALLA. PAUL FIEBIG.

leading up to either side of said doors and means in connection with the same for depressing the said internally-threaded plate when one of the track ends is loaded and for ERNST KATZ, ALBERT SCHENK.

closing the'doors when the rail or track ends l 5 automatically returning the said plate and I Witnesses:

are unloaded substantially as described. l 

